十万个为什么·科学启蒙30篇（2）

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萤火虫如何发出冷光？

Fireflies make light through a chemical reaction called bioluminescence, not heat.
A substance called luciferin reacts with oxygen, aided by an enzyme named luciferase.
This process releases almost all its energy as visible light, not infrared heat.
Because very little heat is produced, scientists call it 'cold light'.
Each firefly species flashes a unique pattern to attract mates in the dark.
Scientists study this reaction to develop safer medical imaging tools for humans.
Unlike light bulbs, firefly light needs no electricity and creates zero waste heat.
Researchers have even inserted firefly genes into plants to make them glow softly.
The color of the light depends on slight changes in the luciferase protein structure.
Nature’s cold-light system remains far more efficient than most human-made LEDs today.